Sewing machine



FIG. 1 is a perspective view of a sewing machine;

FIG. 2 is a front view thereof;

FIG. 3 is a top view thereof; and,

FIG. 4 is an enlarged perspective view thereof.

The broken lines depict environmental subject matter only and form no part of the claimed design. 

The ornamental design for a sewing machine, as shown and described. 